Ink jet printing is a well-known technique by which printing is accomplished without contact between the printing device and the substrate on which the printed characters are deposited. This technique of noncontact printing is particularly well suited for application of characters onto irregularly shaped surfaces, including, for example, the bottom of beverage containers.
Describing briefly one technique for performing ink jet printing, a stream of droplets of ink are projected toward a surface and the trajectories of the droplets are controlled electronically so that the droplets are caused to form the desired printed image on a relatively movable substrate. Another technique of ink jet printing is to direct droplets on demand from a set of orifices at a relatively moving substrate.
In general, ink jet printing techniques impose rigid requirements on the ink compositions. To be suitable for use as a jet ink, the compositions must meet some or all of the requirements of viscosity, resistivity, solubility, compatibility of components and wetability of the substrate. Further, the ink must be quick drying and smear resistant and capable of passing through the ink jet nozzle without clogging. The ink should also permit rapid cleanup of the machine components with minimum effort.
Corrosion of metal parts is a problem presented in many industrial fields, including the field of ink jet printing. Heretofore, it has been difficult to develop ink jet printing formulations which do not promote undue corrosion of metal parts of the ink jet printing apparatus with which the printing ink comes into contact. Often-times it has been necessary to expend substantial time and effort in formulating each particular ink jet formulation to render the same acceptable from the standpoint of minimizing metal corrosion.
A need has therefore existed for corrosion inhibitors which could be incorporated into non-aqueous liquids, such as ink jet formulations, which corrosion inhibitors, while reducing corrosion of metal parts which come into contact with the ink jet formulation, would also not adversely affect the properties of the ink jet itself. As may be appreciated, ink jet formulations must meet very specific, stringent requirements with respect to many particular physicochemical properties, such as electrical conductivity, sonic velocity, viscosity, and the like. If a corrosion inhibitor has an effect on any such property, it may render the ink jet formulation unworkable, without reformulation, requiring the expenditure again, of large quantities of time and effort.
For general applications in fields not requiring such stringent control of physicochemical parameters, many compositions, including dialkyl amines, and derivatives and salts thereof, have been employed as corrosion inhibitors. For example, U.S. Pat. No. 4,975,211 discloses the use of diethylamine complexes of borated alkyl catechols as corrosion inhibitors in lubricating oils. Amine-complexed zinc salts of organic diacids, employing compounds such as zinc dibasate diethylamine, are disclosed in U.S. Pat. No. 4,774,345. U.S. Pat. No. 4,748,011 discloses the use of amines such as diethylamine and dipropylamine as corrosion inhibitors in natural gas formulations. U.S. Pat. No. 4,744,913 discloses the use of dipropylamine and dibutylamine as corrosion inhibitors in de-icing and anti-icing agents for aircrafts. U.S. Pat. No. 4,698,279 discloses the use of diisopropylamine in a back coating layer of magnetic recording tape, to improve the resistance of the magnetic layer to corrosion.
Diisopropylamine nitrite is disclosed as a corrosion inhibitor in a rust preventative, in U.S. Pat. No. 4,677,177. Organic phosphate adducts with diethylamine are discussed in U.S. Pat. No. 4,584,175 as extending corrosion protection to magnesium and its alloys, used in a plastic sheet for enveloping metal objects to be protected. U.S. Pat. No. 4,501,674 discloses the use of diethylamine as an ancillary agent for use in an enzyme system for reducing corrosion, when used in combination with crude oil additives. Diethylamine is also included in an absorption refrigeration system, as shown in U.S. Pat. No. 4,455,247. U.S. Pat. No. 4,433,127 shows room temperature curable silicon compositions which are effective for protecting copper and other metals from corrosion, the composition optionally containing dibutylamine.
U.S. Pat. No. 4,342,596 discloses the use of diisopropylamine in a metal-corrosion inhibiting composition for use as a non-petroleum based metal corrosion inhibitor. Diisopropylamine is also used in cooling water, as disclosed in U.S. Pat. No. 4,338,209, in combination with the metal corrosion inhibitor disclosed in that patent. U.S. Pat. No. 4,295,979 discloses the use of diethylamine as an activator which is believed to be incorporated into alkyl polysulfide used in corrosion inhibitors for gas wells. Diisopropylamine nitrite is again employed as a volatile corrosion inhibitor used in the manufacture of corrosion resistance ferromagnetic metal powders, in accordance with U.S. Pat. No. 4,253,886. U.S. Pat. No. 4,204,972, referring to published German application No. 2,532,228 simply states that dialkylamines such as dibutylamine are known to inhibit corrosion.
The use of disubstituted lower alkyl amines in carbon dioxide propellants, as corrosion inhibitors, is discussed in U.S. Pat. No. 4,161,458. The use of amines such as diethylamine, dipropylamine, and the like in forming certain corrosion inhibiting salts is discussed in U.S. Pat. No. 4,101,328. Ball point pen inks containing diethylamine salt as a corrosion inhibitor is disclosed in U.S. Pat. Nos. 4,077,807 and 4,077,727. U.S. Pat. No. 3,964,927 discloses the use of dibutylamine as a corrosion inhibitor in an electrolyte used in a lead dioxide-zinc rechargeable-type cell and battery. Dibutylamine pyrophosphate is employed as a corrosion inhibitor in an aqueous system, as disclosed in U.S. Pat. No. 3,935,125. U.S. Pat. No. 3,925,223 discloses the use of dipropylamine and dibutylamine as corrosion inhibitors in hydraulic fluids. Diisopropylamine nitrite is disclosed as a corrosion inhibitor used in corrosion inhibiting paper in U.S. Pat. No. 3,891,470.
Despite all of the foregoing uses of dialkyl amines, such as diethyl amine, dipropyl amine, and dibutyl amine, in corrosion inhibiting formulations, either directly, or as salts, derivatives, or complexes, over many years, such amines have never been employed for purposes of corrosion inhibition in ink jet formulations.